Organ pipe with loudspeaker excitation - saves air blowing power and controls harmonics by matching speaker resonance to that of pipe

摘要

The air column in a pipe (4), e.g. of an organ, is excited at its fundamental resonance by a loudspeaker (7) with its diaphragm (9) facing the open end of the pipe. The loud-speaker is driven by a signal at the resonant frequency and its harmonic content controls the tone of the sound produced. The loudspeaker signal can be switched directly without causing unpleasant transients because the pipe resonance is much louder. The pipe resonance build up can be controlled by an air gap (10) between the pipe and the loudspeaker. This method of exciting a pipe uses less power than air blowing.